which may become biennial or perennial. _Alopecurus geniculatus._ _Hordeum pratense._ _Lolium perenne._ _L. italicum_ (may be perennial). _Bromus asper_ (may be perennial). _B. sterilis._ _B. arvensis_ (may be perennial). PERENNIALS. _Holcus lanatus._ _H. mollis._ _Nardus._ _Hordeum sylvaticum._ _Agropyrum._ _Brachypodium._ _Bromus erectus._ _B. giganteus._ _Festuca ovina._ _F. elatior._ _F. sylvatica._ _Dactylis._ _Cynosurus cristatus._ _Briza media._ _Milium._ _Anthoxanthum._ _Digraphis._ _Phleum pratense._ _Alopecurus pratensis._ _Agrostis alba._ _A. canina._ _Psamma._ _Aira cæspitosa._ _A. flexuosa._ _A. canescens._ _Avena pratensis._ _A. flavescens._ _Arrhenatherum._ _Glyceria aquatica._ _G. fluitans._ _Poa maritima._ _P. compressa._ _P. pratensis._ _P. trivialis._ _P. nemoralis._ _P. alpina._ _P. bulbosa._ _Molinia._ _Melica._ _Triodia._ _Kœleria._ _Arundo._ [Illustration: Fig. 4. _Catabrosa aquatica._ Plant showing the creeping habit, rooting nodes, and paniculate inflorescence (reduced). Parnell.] The rhizome of a perennial grass is continued sympodially by means of buds branching from the lowermost joints of the flowering shoots, and some importance is attached to the mode of spreading of these lateral sprouting shoots. The buds always arise in the axils of the lower leaf-sheaths--i.e. they are _intra-vaginal_. If they remain intra-vaginal during further growth, the shoots are forced upwards and only _tufts_ (Fig. 2) are formed, except in so far as such shoots may fall prostrate on the surface of the ground later, and throw out roots from their nodes, and so act as _runners_ or offsets, or put out a few roots &c. as they ascend through the soil. But in many cases the buds soon burst through the leaf-sheaths, and develope as _extra-vaginal_ shoots, and may then run horizontally as underground _stolons_. Only creeping grasses of these latter kinds can rapidly cover large areas[4]: the grasses with intra-vaginal shoots only can only make tufts or “tussocks.” Several peculiarities in the habits of grasses depend on these facts. The following are the most important creeping, or _stoloniferous_ species, contrasted with the much more common _tufted_ and the far rarer grasses with _runners_ above ground (Fig. 4). Some of these (_Elymus_, _Psamma_, &c.) are of great importance as sand-binders.— With intra-vaginal branches only. _Lolium_--slightly stoloniferous. _Festuca elatior_--slightly stoloniferous. _Avena flavescens_--slightly stoloniferous. _Phleum pratense_--no stolons, but may be bulbous. _Dactylis_--no stolons. _Festuca ovina_--no stolons. _Poa alpina_--no stolons. _Cynosurus_--no stolons. With extra-vaginal shoots.